The present invention relates in general to electrical fuel injection systems of an internal combustion engine and in particular to a method of and a device for supervising the operation of a control apparatus which produces control pulses for such injection systems.
Conventionally, motor vehicles are equipped with electric fuel injection systems which achieve an improved fuel consumption and consequently reduced pollution. The electrically controlled fuel injection guarantees that IC engines are without problems supplied with the most effective amount of fuel irrespective of whether the engine operates in its idling, coasting, partially loaded or fully loaded modes of operation. The injection system provides namely an optimum adjustment to the above operational modes and enables the operator to have a well balanced and uniform control of the motor vehicle.
It is true that contemporary mechanical or electrical fuel injection systems operate without problems and failures. On the other hand, it cannot be excluded that under certain circumstances temporary failures may occur in the control apparatus for the electrical fuel injection system for example. Such interferences may consist in a random or repeated skipping of individual control pulses which may occur under certain driving conditions of the motor vehicle only. Such occasional misfunctions in practice cannot be removed by the operator of the vehicle, inasmuch as the complicated construction of electrical or electronic control devices for fuel injection systems prevents an investigation and check-up in this area. On the other hand, any occasional or repeated loss of fuel injection pulses or, on the other hand, an excessive generation of such pulses produces a deviation from the prescribed fuel-air mixture ratio from values prescribed for different operational conditions.